Diverse range of physical and chemical properties.
Metals and nonmetals
Some are highly reactive and some hardly react at all.
o Solids, liquids, and gases at room temperature
Elements in the same group on the periodic table have the same amount of valence electrons, therefore, they have similar physical and chemical properties. Representative elements have valence electrons in the s or p orbitals.
Ionization energy:
As atomic radius increases, or the atom gets larger, the ionization energy decreases.
Lower ionization energy makes it easier for element to lose electrons.
Metals tend to lose electrons, nonmetals gain electrons
Higher the ionization energy in a nonmetal, the more reactive it is, while in metals, the elements are more reactive with lower ionization energy.
Thus, for a group of metals, reactivity increases as the atomic number increases, and for a group of nonmetals, reactivity decreases as the atomic number increases.
Diagonal Relationships:
Some elements in period 2 have more in common with the period 3 elements than the period 3 element in their own group. For example, period 2 element boron has more in common with period 3 element silicon than aluminum has with silicon.
Hydrogen:
1 valence electron
Placed in group 1A, but is more similar to the nonmetals in group 7A.
Has both metallic and nonmetallic properties, so it is not considered part of any group because of its one valence electron.
Was discovered in 1766 by Henry Cavendish.
Cavendish called it “flammable air” because it burned when ignited in air.
It was later given the name “hydrogen” in 1783 by Antoine Lavoisier because water is formed when it combines with oxygen.
It is a gas that is colorless, odorless, and lighter than air.
The universe contains more than 90% hydrogen by mass
3 naturally occurring isotopes
Protium
Majority of hydrogen (99.985%)
No neutrons
Deuterium
Makes up 0.015% of hydrogen
1 neutron
Tritium
2 neutrons
Radioactive
Produced when cosmic rays bombard water in the atmosphere.
Physical properties of isotopes differ slightly because of differences in atomic mass.
When hydrogen acts like a nonmetal, it gains an electron and the stable configuration of helium.
When reacting with a nonmetal such as oxygen, it becomes more like a metal and loses an electron.
Forms hydrogen ion H+
Has a nucleus with only a single proton
Hydrogen can be produced in a lab when a metal reacts with an acid or when it is separated from oxygen in water with the use of electricity.
Major industrial use is production of ammonia from nitrogen and hydrogen gases
Also used to convert liquid vegetable oils into solid fats like shortening.
*Source: Glencoe Science. Chemistry: Matter and Change. 179-180.
Hydrogen (continued)
Hydrogen has one valence (the characteristic that determines the number of atoms or groups of atoms that will combine chemically with another atom or group of atoms) electron which gives hydrogen a weird set of both metallic and non metallic properties.
When an atom of hydrogen (the 1st element of the periodic table of elements) acts like it is a non metal, the hydrogen atom will add an electron to it’s configuration which will give the hydrogen atom the same stable electron configuration as the element helium (the 2nd element of the periodic table of elements).The element hydrogen responds to the non metal element oxygen (the 8th element of the periodic table of elements) it would act as a metal. Hydrogen loses its one electron. The lost electron of hydrogen is then transferred to the anion (a negatively charged ion) of the acid. They hydrogen atom then becomes a positively charged hydrogen ion or (H+) which is a part of all aqueous or watery solutions of acids. A hydrogen ion is a nucleus that has one and only one proton.
Group 1A: Alkali Metals
Group 1A metals respond with water to form alkaline solutions which are called alkali metals. Alkali metals can easily lose a valence electron and form a 1+ charge. Alkaline metals can be cut by a knife because of how soft they are. Alkali metals are highly reactive and are found combined with other elements of nature. Lab samples of alkali metals are stored in oil to prevent being combined with oxygen in the air. Alkali metals are good conductors of heat and electricity.
Lithium
The lightest alkali metal is lithium which can be found in water, soil, and rocks. Lithium is the least reactive of all alkali metals. Its compounds are the least likely to be dissolved when it is combined with water. These properties of lithium keep it closely related to the element magnesium more than other alkali metals. Lithium’s atomic radius is 152 pm. (Pico meter) and it has an ionic radius of 76 pm. Magnesium has an atomic radius of 160 pm. and an ionic radius of 72 pm. magnesium has a diagonal relationship with lithium.
Group 2A: Alkaline Earth Metals
Group 2A elements form compounds with oxygen, called oxides, that qualify as “earths” by definition. (“earths” are solids that won’t melt in fire) Except for beryllium oxide, these oxides produce alkaline solutions when the react with water.
Are shiny solids that are harder than alkali metals.
Are less reactive than alkali metals
Lose their 2 valence electrons to form ions with a 2+ charge.
Most compounds of earth metals do not dissolve easily in water.
Beryllium- Lightest member of group 2A. Found combined with aluminum, silicon, and oxygen in material called beryl. Aluminum and beryllium have similar chemical properties. Beryllium is used to moderate neutrons in nuclear reactors.
Calcium- Essential element for humans. Found widely in nature. Calcium carbonate is compound that is main ingredient in rocks such as limestone, chalk, and marble. Used as abrasive in toothpaste. An abrasive is a hard material used to polish, smooth, or grind a softer material. When calcium carbonate decomposes, it forms oxide of calcium called lime which is an extremely important industrial compound.
Magnesium- Abundant element that can be formed into almost any shape. The oxide of magnesium has such a high melting point that it is used to line furnaces. Plants and humans need magnesium; plants for chlorophyll and humans for muscle function and metabolism.
Uses of other alkaline earth metals- Strontium gives some fireworks crimson color. Barium is used in paints and in some types of glass and as a diagnostic tool for internal medicine. Radium used to be used to paint the hands on watches because paint containing radium glows in dark.
PG. 182
Long-lasting lithium batteries may extend the ranger of electric automobiles. Compounds of lithium are used in dehumidifiers to absorb water. Lithium carbonate is used to strengthen glass and as a drug to treat bipolar disorders.
Alloys of lithium, magnesium, and aluminum are used for items such as airplane parts because these parts must be strong, yet lightweight. Alloy is used as a solid solution. A chemist can fine-tune the properties of an alloy by varying the amount of each element.
Sodium and Potassium
The most abundant alkali metals
Potassium is more reactive than sodium and more expensive to produce.
Humans and other vertebrates must have sodium and potassium in their diets because many biological functions are controlled by sodium and potassium ions.
When a nerve cell is stimulated, sodium flows in and potassium flows out. This flow of ions across the cell membrane carries the nerve impulse along the cell. After the impulse passes, a compound attached to the cell membrane uses energy to move the ions back across the membrane so that they are in position for the next impulse.
Other Alkali Metals
The most reactive alkali metals-rubidium, cesium, and francium-have little commercial use.
Share properties such as electrical conductivity, luster, and malleability with other metals
Little variation in atomic size, electronegativity, and ionization energy across period
There are differences in properties, especially physical
Physical properties determined by electron configuration
Most transition metals are hard solids, with high melting points and boiling points
Differences in properties based on ability of unpaired d electrons to move up into the next valence level
More unpaired electrons in d sublevel the greater the hardness and higher melting points and boiling points of metal
Formation of Ions
· An ion is formed when an atom loses or gains an electron
· Losing electrons results in a positive charge
· Gaining electrons results in a negative charge
· Positive ions can have a charge of up to 6+
· Most compounds of transition metals have colour.
o The metal ions in these compounds have partially filled d sublevels
o Electrons in these sublevels can absorb visible light of specific wavelengths
o Exceptions are white compounds that contain scandium, titanium, or zinc
o Scandium and titanium ions have empty d sublevels
o Zinc ion has a completely filled and stable d sublevel
o Electrons in these three ions can be excited to higher levels, but not by visible light
o These compounds respond to wavelengths in the ultraviolet range
· If a transition metal can form more than one type of ion, a change from one to another can often be detected by a colour change
Sources of Transition Metals
Copper, silver, gold, platinum, and palladium are the only transition metals that are unreactive enough to be found, pure, in nature.
The rest of the transition metals are found in nature combined with nonmetals, usually in oxides, sulfides, or with other minerals in ores.
Copper, as it is found in nature. Metallurgy is the branch of science that works with extracting metals from ores.
There are three groups of methods for metallurgy:
Those that use high temperatures
Those that use solutions
Those that use electricity
Many countries’ economies rely on their source of transition metals. Places with an abundance of useful transition metals include Canada, Zaire, Democratic Republic of the Congo, and South Africa.
Magnetism & Metals:
Magnetism is the ability of a substance to be affected by a magnetic field. A moving electron creates a magnetic field.
Because paired electrons spin in opposite directions, their magnetic fields tend to cancel out. When all electrons in an atoms or ions are paired with another electron, the substance is slightly affected, if affected at all.
This property is called diamagnetism.
When there is an unpaired electron in the valence orbital of an atom or ion, the electron is attracted to a magnetic field.
This property is called paramagnetism.
Most substances act as temporary magnets: meaning their magnetic properties disappear after the magnetic field is removed.
Transition Metals iron, cobalt, and nickel have a property called ferromagnetism. Ferromagnetism is the strong attraction of a substance to a magnetic field. The ions align themselves in the direction of the field. When the field is removed, the ions stay aligned and the metals continue to act as a magnet. Thus, iron, cobalt, and nickel can form permanent magnets.
Uses of Transition Metals
Copper is used in electrical wiring.
Zinc is used as protective coating for other metals.
Iron is used in making steel.
Many are found in alloys which are used to make things such as engines, drill bits, surgical instruments, and armor.
Plastics, petroleum, and food industries use transition metals such as platinum, palladium, and nickel to control the conditions at which a reaction will occur.
Our bodies need large amounts of some elements to function: carbon, oxygen, hydrogen, nitrogen, sulfur, phosphorus, sodium, potassium, calcium, magnesium, and chlorine. There are other essential elements, but only in small amounts.
Except for scandium and titanium, all period 4 transition metals play vital roles in organisms.
Iron (ions), Manganese, copper, and cobalt all help in some way with cells.
Halogens
Halogens are a series of nonmetal elements from group 17 on the periodic table. This group includes flourine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). There is also a “undiscovered” element (ununseptium) that might also be a halogen.
Halogens are highly reactive. In sufficient amounts, they can be harmful/lethal to biological organisms. The reason why they are so highly reactive is because their atoms outer shells are one atom short of 8 electrons. Through reacting with other elements they can gain the electron that they need to have a full 8.
Bromine and chlorine are used as disinfectants to kill bacteria and other harmful microorganisms. If you were to fall and scrape your knee and need to clean it off, that’s what you would really be using. They are also used to disinfect our drinking water, swimming pools, dishes, and surfaces. Chlorine is used to bleach paper products and fabrics.
-Named for their ability to form compounds with almost all metals.
-Because these compounds are called salts, the elements are called “salt formers” or halogens.
-Halogens differ in their physical properties.
-Chemical behavior is similar with only one exception. Astatine is a radioactive element with no known uses.
-The elements share the following general properties:
-reactive non-metals
-always found combined with other elements in nature
-have 7 valence electrons
-generally forms ions with a 1- charge
Fluorine
-Halogen with the lowest atomic number, so it has a small atom that provides little shielding of its valence electrons from the nucleus.
-Most electronegative element on the periodic table. It has the greatest tendency to attract electrons. Also the most active element
-Reacts with every element except helium, neon, and argon.
-The mineral fluorite, which contains fluoride and calcium, is used to lower the melting points of other minerals to make it easier to separate them from their ores.
-Fluorine compounds are added to toothpaste and drinking water to protect tooth enamel from decay.
-A compound of fluorine and carbon provides a non-stick coating on pots and pans.
Chlorine
-Reacts with nearly all elements.
-Chlorine is a deadly gas, but it has many uses, some which save lives.
-Chlorine compounds are used as bleaching agents by textile and paper industries.
-Hydrochloric acid in your stomach helps digest food.
Bromine and Iodine
-Few commercial uses for their compounds.
-Your body needs iodine to maintain a healthy thyroid gland. This gland produces hormones the control growth and your metabolic rate.
-Seafood is a good source of iodine.
-Campers use iodine to disinfect water.
There are five known halogens bromine, idodine, chlorine, flourine, and astatine. Halogens are non-metallic elements found in group 17. They are highly reactive, and only found as compounds or ions.
At room temperature fluorine and chlorine are gases, bromine is a liquid and iodine and astatine are solids.
Noble Gases
Among the last naturally occurring elements to be discovered because they are colorless and unreactive.
Known for their stability
Have maximum number of electrons in their outermost energy level.
Helium
Lightest Noble Gas.
Found on earth in natural gas wells.
Used in blimps, airships, and balloons.
Liquid helium is used as a coolant for superconducting magnets.
Neon
Used in light displays that are commonly referred to as neon lights
Color of neon lights is not constant because gases other than neon can be used in the displays.
Argon and Krypton
Argon is most abundant of the noble gases on Earth, makes up about 1% of Earth’s atmosphere.
Provides an inert atmosphere for procedures such as high-temperature welding.
Both used to prolong the life of filaments in incandescent light bulbs and as a layer of insulation between panels of gas.
Inner Transition Metals
Lanthanide Series
Silvery Metals
High Melting Points
Very little variation between two elements in the series they are found mixed together and are very hard to separate.
Actinide Series
Radioactive elements
Only three exist in nature, the rest are synthetic elements called transuranium elements, an element with an atomic number greater that 92.
Transuranium elements are created in partial accelerators or nuclear reactor.
Most decay quickly; one exception is plutonium-239 that can stay radioactive for thousands of years.
Group 3A: The Boron Group
*Group 3A elements are always found combined with other elements in nature
*Most often found as oxides in Earth's crust
*Group 3A contains one metalloid (boron), one metal (aluminum), and three rare metals (gallium, indium, and thallium) Boron
+Boronis one of the seven micronutrients essential to all plant growth
+used in reactor control rods +melting point: 205°C+Main Source of Boron is a complex compound of boron called "borax"
+Half of the world's supply of borax comes from a large deposit in California's Mojabe Desert.
+Borax is used as a cleaning agent and as fireproof insulation
+Boric acid is another compound of boron and is used as a disinfectant and as an eye wash
+Boron Nitride is the second hardest known material
Aluminum
+Aluminum is the most abundant metal and third most abundant resource in the earth's crust
+Aluminum oxideis the major compund in bauxite
+ The compud aluminum sulfate, known as alum, is used in antiperspirants and to remove supended particles during water purification
Gallium
+Gallium is used in some thermometers because it remains a liquid over a wide temperature range : 30°C to 2403 °C + A compound of gallium and arsenic called gallium arsenide produces and electric current when it absorbs light
Silicon
+Silicon is used in computer chips andsolar cells
+It is the second most abundant element in the earth's crust, afteroxygen
+Occurs most often when combined with oxygen in the compound silicon dioxide, also known as silica
Lead and Tin
+Lead is toxic
+Bronze is an alloy of tin and copper with copper being predominate
+Pewter is made 40 percent lead and 60 percent tin until toxic effects of lead become known
+Lead may have been the first pure metal obtained from its ores because of its low melting point
+Ancient skeletons have shown significant levels of lead
+Until people realized the dangers of lead poisoning, lead was used for eating utensils, pipes, and as andadditive in gasoline
+Lead is especially harmful for preschool children who may inhale it in dust or chew on scraps of peeling paint
Carbon
+ Carbon is found in many everday items such as food, clothes, and cosmetics.
+It is the sixth most common element in the universe
+Diamonds and graphite are two types of carbon
+Melting Point: 3550 ºC +Boiling point: 3825ºC
+It is also one of the most important elements on Earth
GROUP 5A: THE NITROGEN GROUP
-Nitrogen (N symbol and atomic number 7) gas is colorless, odorless, and relatively unreactive.
-About 78% of Earth’s atmosphere is nitrogen. -Ammonia (nitrogen compound ammonia) (in cleaning products) is a colorless gas with an irritation odor.
About 25% of ammonia is converted into nitric acid—for explosives, dyes, and solid fertilizers.
-Some nitrogen compounds are extremely unstable, these include TNT and nitroglycerine.
-Phosphorus (P symbol and atomic number 15) -Allotrope – any of several crystalline forms of a chemical element. (Red phosphorus, white phosphorus, and black phosphorus) -White phosphorus bursts into flames in air and must be stored in water. -Red phosphorus is less reactive and forms when white phosphorus is heated in the absence of air. (Red phosphorus is used on the striking surface of matchboxes.) -Black phosphorus is produced when either red or white phosphorus is heated under high pressure.
-Phosphorus is essential for plant growth. Most phosphorus is used to make phosphoric acid, which is converted into phosphate compounds (in cheese, laxatives, baking powders, and grease removers).
-The use of fertilizers containing phosphates can be harmful to the environment. Algae feed on nutrients that include phosphate ions.
-Arsenic (As symbol and atomic number 33), antimony (Sb symbol and atomic number 51), and bismuth (Bi symbol and atomic number 83) are less abundant than nitrogen and phosphorus. -Arsenic is toxic, but physicians used small amounts of an arsenic and sulfur compound, arsenic sulfide, to treat some illnesses.
-Lead storage batteries contain 5% antimony. A black compound of antimony and sulfur, antimony sulfide, was used as a cosmetic to darken eyebrows to make eyes appear larger. -Britannia metal, an alloy of tin and antimony, can be shaped by stamping or spinning and cast in molds.
-A compound of bismuth is the active ingredient in Pepto-Bismol. A low-melting alloy of bismuth, lead, tin, and cadmium called Wood’s metal is used as a plug in automatic sprinkler systems.
- Groups 1A through 8A
- Diverse range of physical and chemical properties.
- Metals and nonmetals
- Some are highly reactive and some hardly react at all.
o Solids, liquids, and gases at room temperatureDiagonal Relationships:
Hydrogen:
*Source: Glencoe Science. Chemistry: Matter and Change. 179-180.
Hydrogen (continued)
Hydrogen has one valence (the characteristic that determines the number of atoms or groups of atoms that will combine chemically with another atom or group of atoms) electron which gives hydrogen a weird set of both metallic and non metallic properties.
When an atom of hydrogen (the 1st element of the periodic table of elements) acts like it is a non metal, the hydrogen atom will add an electron to it’s configuration which will give the hydrogen atom the same stable electron configuration as the element helium (the 2nd element of the periodic table of elements).The element hydrogen responds to the non metal element oxygen (the 8th element of the periodic table of elements) it would act as a metal. Hydrogen loses its one electron. The lost electron of hydrogen is then transferred to the anion (a negatively charged ion) of the acid. They hydrogen atom then becomes a positively charged hydrogen ion or (H+) which is a part of all aqueous or watery solutions of acids. A hydrogen ion is a nucleus that has one and only one proton.
Group 1A: Alkali Metals
Group 1A metals respond with water to form alkaline solutions which are called alkali metals. Alkali metals can easily lose a valence electron and form a 1+ charge. Alkaline metals can be cut by a knife because of how soft they are. Alkali metals are highly reactive and are found combined with other elements of nature. Lab samples of alkali metals are stored in oil to prevent being combined with oxygen in the air. Alkali metals are good conductors of heat and electricity.
Lithium
The lightest alkali metal is lithium which can be found in water, soil, and rocks. Lithium is the least reactive of all alkali metals. Its compounds are the least likely to be dissolved when it is combined with water. These properties of lithium keep it closely related to the element magnesium more than other alkali metals. Lithium’s atomic radius is 152 pm. (Pico meter) and it has an ionic radius of 76 pm. Magnesium has an atomic radius of 160 pm. and an ionic radius of 72 pm. magnesium has a diagonal relationship with lithium.
Group 2A: Alkaline Earth Metals
Beryllium- Lightest member of group 2A. Found combined with aluminum, silicon, and oxygen in material called beryl. Aluminum and beryllium have similar chemical properties. Beryllium is used to moderate neutrons in nuclear reactors.
Calcium- Essential element for humans. Found widely in nature. Calcium carbonate is compound that is main ingredient in rocks such as limestone, chalk, and marble. Used as abrasive in toothpaste. An abrasive is a hard material used to polish, smooth, or grind a softer material. When calcium carbonate decomposes, it forms oxide of calcium called lime which is an extremely important industrial compound.
Magnesium- Abundant element that can be formed into almost any shape. The oxide of magnesium has such a high melting point that it is used to line furnaces. Plants and humans need magnesium; plants for chlorophyll and humans for muscle function and metabolism.
Uses of other alkaline earth metals- Strontium gives some fireworks crimson color. Barium is used in paints and in some types of glass and as a diagnostic tool for internal medicine. Radium used to be used to paint the hands on watches because paint containing radium glows in dark.
PG. 182
Long-lasting lithium batteries may extend the ranger of electric automobiles. Compounds of lithium are used in dehumidifiers to absorb water. Lithium carbonate is used to strengthen glass and as a drug to treat bipolar disorders.
Alloys of lithium, magnesium, and aluminum are used for items such as airplane parts because these parts must be strong, yet lightweight. Alloy is used as a solid solution. A chemist can fine-tune the properties of an alloy by varying the amount of each element.
Sodium and Potassium
The most abundant alkali metals
Potassium is more reactive than sodium and more expensive to produce.
Humans and other vertebrates must have sodium and potassium in their diets because many biological functions are controlled by sodium and potassium ions.
When a nerve cell is stimulated, sodium flows in and potassium flows out. This flow of ions across the cell membrane carries the nerve impulse along the cell. After the impulse passes, a compound attached to the cell membrane uses energy to move the ions back across the membrane so that they are in position for the next impulse.
Other Alkali Metals
The most reactive alkali metals-rubidium, cesium, and francium-have little commercial use.
Formation of Ions
· An ion is formed when an atom loses or gains an electron
· Losing electrons results in a positive charge
· Gaining electrons results in a negative charge
· Positive ions can have a charge of up to 6+
· Most compounds of transition metals have colour.
o The metal ions in these compounds have partially filled d sublevels
o Electrons in these sublevels can absorb visible light of specific wavelengths
o Exceptions are white compounds that contain scandium, titanium, or zinc
o Scandium and titanium ions have empty d sublevels
o Zinc ion has a completely filled and stable d sublevel
o Electrons in these three ions can be excited to higher levels, but not by visible light
o These compounds respond to wavelengths in the ultraviolet range
· If a transition metal can form more than one type of ion, a change from one to another can often be detected by a colour change
Sources of Transition Metals
Copper, silver, gold, platinum, and palladium are the only transition metals that are unreactive enough to be found, pure, in nature.
The rest of the transition metals are found in nature combined with nonmetals, usually in oxides, sulfides, or with other minerals in ores.
Copper, as it is found in nature.
Metallurgy is the branch of science that works with extracting metals from ores.
There are three groups of methods for metallurgy:
- Those that use high temperatures
- Those that use solutions
- Those that use electricity
Many countries’ economies rely on their source of transition metals. Places with an abundance of useful transition metals include Canada, Zaire, Democratic Republic of the Congo, and South Africa.Magnetism & Metals:
Uses of Transition Metals
Halogens
Halogens are a series of nonmetal elements from group 17 on the periodic table. This group includes flourine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). There is also a “undiscovered” element (ununseptium) that might also be a halogen.
Halogens are highly reactive. In sufficient amounts, they can be harmful/lethal to biological organisms. The reason why they are so highly reactive is because their atoms outer shells are one atom short of 8 electrons. Through reacting with other elements they can gain the electron that they need to have a full 8.
Bromine and chlorine are used as disinfectants to kill bacteria and other harmful microorganisms. If you were to fall and scrape your knee and need to clean it off, that’s what you would really be using. They are also used to disinfect our drinking water, swimming pools, dishes, and surfaces. Chlorine is used to bleach paper products and fabrics.
-Named for their ability to form compounds with almost all metals.
-Because these compounds are called salts, the elements are called “salt formers” or halogens.
-Halogens differ in their physical properties.
-Chemical behavior is similar with only one exception. Astatine is a radioactive element with no known uses.
-The elements share the following general properties:
-reactive non-metals
-always found combined with other elements in nature
-have 7 valence electrons
-generally forms ions with a 1- charge
Fluorine
-Halogen with the lowest atomic number, so it has a small atom that provides little shielding of its valence electrons from the nucleus.
-Most electronegative element on the periodic table. It has the greatest tendency to attract electrons. Also the most active element
-Reacts with every element except helium, neon, and argon.
-The mineral fluorite, which contains fluoride and calcium, is used to lower the melting points of other minerals to make it easier to separate them from their ores.
-Fluorine compounds are added to toothpaste and drinking water to protect tooth enamel from decay.
-A compound of fluorine and carbon provides a non-stick coating on pots and pans.
Chlorine
-Reacts with nearly all elements.
-Chlorine is a deadly gas, but it has many uses, some which save lives.
-Chlorine compounds are used as bleaching agents by textile and paper industries.
-Hydrochloric acid in your stomach helps digest food.
Bromine and Iodine
-Few commercial uses for their compounds.
-Your body needs iodine to maintain a healthy thyroid gland. This gland produces hormones the control growth and your metabolic rate.
-Seafood is a good source of iodine.
-Campers use iodine to disinfect water.
There are five known halogens bromine, idodine, chlorine, flourine, and astatine.
Halogens are non-metallic elements found in group 17. They are highly reactive, and only found as compounds or ions.
At room temperature fluorine and chlorine are gases, bromine is a liquid and iodine and astatine are solids.
Noble Gases
Among the last naturally occurring elements to be discovered because they are colorless and unreactive.
Known for their stability
Have maximum number of electrons in their outermost energy level.
Helium
Lightest Noble Gas.
Found on earth in natural gas wells.
Used in blimps, airships, and balloons.
Liquid helium is used as a coolant for superconducting magnets.
Neon
Used in light displays that are commonly referred to as neon lights
Color of neon lights is not constant because gases other than neon can be used in the displays.
Argon and Krypton
Argon is most abundant of the noble gases on Earth, makes up about 1% of Earth’s atmosphere.
Provides an inert atmosphere for procedures such as high-temperature welding.
Both used to prolong the life of filaments in incandescent light bulbs and as a layer of insulation between panels of gas.
Inner Transition Metals
Lanthanide Series
Silvery Metals
High Melting Points
Very little variation between two elements in the series they are found mixed together and are very hard to separate.
Actinide Series
Radioactive elements
Only three exist in nature, the rest are synthetic elements called transuranium elements, an element with an atomic number greater that 92.
Transuranium elements are created in partial accelerators or nuclear reactor.
Most decay quickly; one exception is plutonium-239 that can stay radioactive for thousands of years.
Group 3A: The Boron Group
*Group 3A elements are always found combined with other elements in nature
*Most often found as oxides in Earth's crust
*Group 3A contains one metalloid (boron), one metal (aluminum), and three rare metals (gallium, indium, and thallium)
Boron
+Boron is one of the seven micronutrients essential to all plant growth
+used in reactor control rods
+melting point: 205°C+Main Source of Boron is a complex compound of boron called "borax"
+Half of the world's supply of borax comes from a large deposit in California's Mojabe Desert.
+Borax is used as a cleaning agent and as fireproof insulation
+Boric acid is another compound of boron and is used as a disinfectant and as an eye wash
+Boron Nitride is the second hardest known material
Aluminum
+Aluminum is the most abundant metal and third most abundant resource in the earth's crust
+Aluminum oxide is the major compund in bauxite
+ The compud aluminum sulfate, known as alum, is used in antiperspirants and to remove supended particles during water purification
Gallium
+Gallium is used in some thermometers because it remains a liquid over a wide temperature range : 30°C to 2403 °C
+ A compound of gallium and arsenic called gallium arsenide produces and electric current when it absorbs light
Silicon
+Silicon is used in computer chips and solar cells
+It is the second most abundant element in the earth's crust, after oxygen
+Occurs most often when combined with oxygen in the compound silicon dioxide, also known as silica
Lead and Tin
+Lead is toxic
+Bronze is an alloy of tin and copper with copper being predominate
+Pewter is made 40 percent lead and 60 percent tin until toxic effects of lead become known
+Lead may have been the first pure metal obtained from its ores because of its low melting point
+Ancient skeletons have shown significant levels of lead
+Until people realized the dangers of lead poisoning, lead was used for eating utensils, pipes, and as and additive in gasoline
+Lead is especially harmful for preschool children who may inhale it in dust or chew on scraps of peeling paint
Carbon
+ Carbon is found in many everday items such as food, clothes, and cosmetics.
+It is the sixth most common element in the universe
+Diamonds and graphite are two types of carbon
+Melting Point: 3550 ºC
+Boiling point: 3825ºC
+It is also one of the most important elements on Earth
GROUP 5A: THE NITROGEN GROUP
-Nitrogen (N symbol and atomic number 7) gas is colorless, odorless, and relatively unreactive.
-About 78% of Earth’s atmosphere is nitrogen.
-Ammonia (nitrogen compound ammonia) (in cleaning products) is a colorless gas with an irritation odor.
About 25% of ammonia is converted into nitric acid—for explosives, dyes, and solid fertilizers.
-Some nitrogen compounds are extremely unstable, these include TNT and nitroglycerine.
-Phosphorus (P symbol and atomic number 15)
-Allotrope – any of several crystalline forms of a chemical element. (Red phosphorus, white phosphorus, and black phosphorus)
-White phosphorus bursts into flames in air and must be stored in water.
-Red phosphorus is less reactive and forms when white phosphorus is heated in the absence of air. (Red phosphorus is used on the striking surface of matchboxes.)
-Black phosphorus is produced when either red or white phosphorus is heated under high pressure.
-Phosphorus is essential for plant growth. Most phosphorus is used to make phosphoric acid, which is converted into phosphate compounds (in cheese, laxatives, baking powders, and grease removers).
-The use of fertilizers containing phosphates can be harmful to the environment. Algae feed on nutrients that include phosphate ions.
-Arsenic (As symbol and atomic number 33), antimony (Sb symbol and atomic number 51), and bismuth (Bi symbol and atomic number 83) are less abundant than nitrogen and phosphorus.
-Arsenic is toxic, but physicians used small amounts of an arsenic and sulfur compound, arsenic sulfide, to treat some illnesses.
-Lead storage batteries contain 5% antimony. A black compound of antimony and sulfur, antimony sulfide, was used as a cosmetic to darken eyebrows to make eyes appear larger. -Britannia metal, an alloy of tin and antimony, can be shaped by stamping or spinning and cast in molds.
-A compound of bismuth is the active ingredient in Pepto-Bismol. A low-melting alloy of bismuth, lead, tin, and cadmium called Wood’s metal is used as a plug in automatic sprinkler systems.